Fabrication And Characterization Of Silver Transparent Flexible Conductive Thin Film

As electronic devices develop towards miniaturization, integration and lightweight, metal oxide conductive film, represented by ITO(Indium Tin Oxide) is increasingly difficult to meet the requirements. The main reasons are as following:(1) The metal oxide thin film is brittle and may easy to crack or peel off after several bends or folds, due to its fragility. Thus, metal oxide is difficult to meet the needs of flexible electronic devices.(2) Most of the metal oxide thin film growth techniques, such as chemical vapor deposition(CVD), vacuum evaporation, pulsed laser deposition(PLD), magnetron sputtering deposition, not only require complicated fabrication process, but may also involve high temperature, which exceeds the range that flexible substrate can bear.Flexible transparent conductive film, represented by silver nanowires and silver mesh, can bear repeated folding and flexing. At the same time, the film can be fabricated in ambient temperature. Therefore, metal nanowire and metal mesh technologies are becoming the most promising conductive material replacing ITO in flexible display, touch screen, solar cell, and other fields.The research content of this thesis mainly includes the following aspects:(1) Polyol-thermal approach to synthesize silver nanowires was conducted. Products of different morphologies were gained by adjusting the reaction conditions, such as the addition of Polyvinylpyrrolidone(PVP), the addition of FeCl3?6H2O, the molecular weight of Polyvinylpyrrolidone(PVP). Role of each reaction condition is discussed.(2) Silver nanowire network laid over a layer of ethylcellulose on the flexible substrate were fabricated by several cross bar coatings at 90° angel of each other. The influence of silver nanowires mass percentage and aspect ratios on the photo and electric properties of thus generated flexible transparent conductive film is discussed, and flexibility is also characterized.(3) Micron-sized groove pattern with continuous pathway were fabricated on the flexible substrate, after which conductive silver paste were filled in. Silver mesh was obtained through two steps: first, extra conductive silver paste on the surface of the flexible substrate should be removed; second, the remaining silver paste in the groove should be sintered to form a continuous structure. The visible light transmittance and sheet resistance of the conductive films of different groove depth were characterized and discussed.